ABSTRACT
Determination of the pastoral value of natural vegetation in the subhumid Mediterranean zone of Chile, and its relation with stocking rate

Carlos Ovalle M.1, Julia Avendaño R.1, Michel Etienne2, Mélica Muñoz S.3 y María Teresa Serra3
 

The metodology of phytological analysis, proposed by CEPE-L. 'Emberger, Montpellier, France, is illustrated by its application to a sheep stocking-rate trial sheeps/ha.
The method utilized considers 4 steps: a) maping of the vegetation, based on plant communities, vegetation cover and dominant species; this maping emphasizes the vegetation heterogenity and permits the stratification for the sampling of the plots; b) evaluation of the dry matter production; c) determination of the botanical compasition of the range, utilyzing the modified "point-quadrat" method; d) determination of the pastoral value (VP) of the vegetation, in order to rank relate the ranges, at the different stocking rates, according to their productivity and quality.
The present study, done four years after initiation of in a Mediterranean, subhumid, dry annual range. Seven stocking rates were considered, ranging from 1 to 4 sheeps/ha, with intermediate interval of 0.5 the stocking rate trial, established that the changes in the range vegetation, due to the different stocking rates, are in active evolution. The treatments of 1 and 1.5 sheeps/ha had a VP higher than 20 points; between 1.5 and 2 sheeps/ha, a marked drop in VP was observed down to a VP of 9, in the 4 sheeps/ha treatment.
Based on the results obtained, the stocking rate of 1.5 sheeps/ha/year, appeared to be the most stabilized. Also it can be proposed that the relation between stocking rate and VP, for the Suffolk Downbreed, is: 1 sheep/ha/year = 15 VP points. This relationship should be more acurately defined in the future, to better estimate the optimum stocking rate for the ranges in this zone.

Keywords:
1lngs. Agrs., Subestación Experimental Cauquenes (INIA), Casilla 1.65, Cauquenes, Chile.
2 lng. Agr., Dr., Centre d'Etudes Phytosociologiques et Ecologiques Louis Embargar (CEPE), Boite postale 5051, 34033, Montpellier, Francia.
3A cargo determinación botánica: Ing. Agr., Sección Botánica, Museo Nacional de Historia Natural, Casilla 787,Santiago, Chile, y Prof., Facultad de Ciencias Forestales, Universidad de Chile, Casilla 9205, Santiago, Chile.